The differences are enormous and to answer this question would
take many pages. Briefly let us look at some key differences. Aircraft
price guides are published, marketed, and distributed by book publishing
companies. The facts are, they do not appraise aircraft, they do not
even gather or generate their own data. Rather, they simply send out a
questionnaire every 3 months to subscribers of their books and ask a few
questions which at best are very vague. From these questionnaires the
book publishers generate their data base.
An interesting point to consider is this. Nowhere on these
questionnaires do the price guide book publishers request information
|The aircraft's damage history.
|Engine or airframe modifications, if any.
|Make and model of installed avionics and if there were any
|Physical condition of the airframe including surface corrosion
|Inspection status of the aircraft. For example, the aircraft
may have been out of Annual for some period of time or/and there may
be Airworthiness Directives and/or mandatory Service Bulletins which
have not been complied with.
|Props and time since overhaul.
|Engine overhaul status. For example, was the engine field
overhauled to FAA overhaul service limits or overhauled to factory
new limits or a new engine.
|Condition of de-ice equipment, instrumentation and other
systems and components.|
It is truly a mystery how one could generate an accurate database
of aircraft values without a clue regarding the condition of the
airframe, make and model of avionics, damage history, airframe or engine
modifications and all of the other important value points listed above.
The National Aircraft Appraisers Association is the only organization in
the world which considers all of these factors in its database.
Additionally, all of the information the National Aircraft Appraisers
Association uses is verified by its members who have physically
evaluated the aircraft and each Association member subscribes to the
same evaluation criteria while performing the appraisal. The end result
is an extremely accurate database that is verifiable.